Improvement in sewing-machines



UNITED STATES PATENT OFFICE.

oYEUs w. BALDWIN, on BoSfroN, MASSACHUSETTS.

IMPROVEMENT IN SEWING-MACHINES.

Specification forming part (if-Letters Patent No. 39,207, dated July 14, 1863.

the letters thereon.

My invention consists of a device or mechanism which, attached to the main shaft of the machine bythe eccentric straps androds hereinafter described, and loperating in connection with the upper needle, enables me to construct or make what is known as the elastic doublej ,loop or chain stitch. My new device for form- 'ing'r this stitch is, so far as I am aware, much more simple and certain than any other in use, as my method for carrying the looper or lower needle around the upper needle renders the dropping of a stitch almost an impossibility, and at the same time dispenses altogether with the spreader used in.other machines, which, byits. operation, constantly wears and often breaks the thread. l

Having describedthe nature of my invention, l will now describe its construction and operation to enable others skilled in such matters to make and use the same.

In the accompanying drawings, Figure l is a bottom view of a sewing-machine constructed according tominvention. Fig. 2 is a vertical and transverse section of the same. Fig. 3 is'a vertical and longitudinal section of a portion otl the main or driving shaft and the cccentrics secured thereto, as hereinafter described. Fig. 4 shows the relative positions ot' the eccentrics as secured to the drivingshaft, and the difference between their points of throw. ln these drawings, A represents the table of the machine, B the drivingshaft, C the needleholder, and D the needle, all these being con structed and operating in a mannercommon to many sewing-machines. n

'.lhe driving-shalt -B revolves in standards or bearings E E, and on the end of such shaft nearest the needle are secured, by set-screws or otherwise, thetwo eccentrics Fand G, around which pass the bands H and I, which, by the rods J and K and the studs-L and M, are coniiected to the vibrating bars or levers N and O. These eccentrics F and G are attached to the main or driving shaft in such relative positions that the point. of throw or feathered point of one from its center differs from the like point ot' the other about eighty-live degrecs, as seen in Fig. 4, and they impart their motion accordingly.

N is a straightvibrating bar, turning upon the stud P, by which it is secured to the under side of the table, (see Fig.. 1,) motion being communicated to it from the eccentric F by means of the band H, the rod J, and thestud M.

0 is an angular bar or bent lever, pivoted at and by the studf upon the straight bar N, and receiving motion therefrom, the long arm of which, c, bears the under needle or loopere, and the short arm ot' which, b, is pivoted to the rod K at and by the stud L, the said rod K being connected with the band I, which encircles and receives motion from the other eccentric, G. Thus the said bentlever() is subjected to acompound motionmadcupot tbemotion received i'roin'the straight bar N and that received from the eccentric G. The lower needle or looper, e, attached, as above described, to the arm c of the bent lever O, is by this compound motion carried forward on one side of the upper needle as said upper needle is ascending, and backward on its other side as it is descending, and thus passing in a curve o'r ellipse completely around the point of the upper needle, and forming in combination there with a succession of loops which constitute the elastic double -loop or lockstitch in the usual form. v

`I have here described in detail only the mechanism comprised in my present improvement,'tlie other operating parts ofthe machine being common to many sewing-machines.

Having now described my invention, what I claim, and desire to secure by Letters Patent, 1s

The vibrating bars or levers N and O, as operated by the eccentrics Fand G, by means ofthe bands H and I, the rods J and K, and the studs L and M, or their equivalents, in combination with each other and with thclooper or lower needle, operated as above described, and for the purposes herein set fort-h.

CYRUS BALDWIN.

Witnesses:

HENRY DENNY, S. EDWIN IvEsoN. 

